The present invention relates to an apparatus for supporting a hand guided drill tool, especially a drill tool having diamond cutting elements.
The initial drilling process is especially critical during a hand guided drilling operation. As a result of a deficient guiding of the drill cutting element into the drilled hole, the drill cutting element may work itself out of the hole due to the rotation of the tip of the drill cutting element. Damage to the outer surface of the piece being drilled is thus unavoidable. For this reason, it is preferred to use a support element, which is also known as an initial drilling aide, for the initial drilling process. The support element is intended to provide additional assistance in standing off the drill tool from the outer surface of the piece to be drilled. Moreover, such support elements serve as holders for a retaining ring for cooling or lubrication medium during wet drilling processes.
It is known to use support elements which are attachable to drill tools and which have, at the drill cutting element location, a stand off receiving member for concentrically receiving and surrounding the drill cutting element to support the drill tool relative to the outer surface to be drilled. Such known support elements include one or two spring biased retractable support arms which, in their fully extended position from a base support element spaced from the outer surface, are pressed against a travel limit member under the action of the spring bias. Such support elements are disadvantageous in that the retractable support arms periodically hit hard against the travel limit member while returning to their extended positions. The danger thus arises that constituent elements of the support element will be damaged with the support element consequently not suited for further use. Additionally, undesired collision noises are produced.